Hi, Jennifer!
Welcome back to the Disney Parks Moms Panel! I love finding new ways to enjoy the fireworks over Magic Kingdom Park.
I am lucky to have enjoyed
Ferrytale Wishes: A Fireworks Dessert Cruise last November. I had the same questions you had when I was in the park and worried about missing the cruise. It turns out, you need to take the Ferry from the Magic Kingdom to the Transportation and Ticket Center. Once you get off the ferry, you'll notice a seating area with an overhang with some shade. You should see a few Cast Members checking in Guests who have reservations for the special cruise. If you can't find it, just be sure to ask the first Cast Member you find and I'm sure they'll be able to direct you.
My best tip: The upstairs, right corner of the ferry will have the best spots to snack on your treats and see the fireworks show. There are PhotoPass photographers who can take your pictures before, during and after the show. If you don't snag a spot in the corner, don't worry. Guests are very generous about sharing the views so we could all enjoy the experience.
I hope you have an unforgettable vacation next month! Let me know if I can answer any extra questions before your arrival.
-Jen